Tag Archives: pleistocene

Move Over Wolves, it’s Time for Cougars and Donkeys

A novel trophic cascade between cougars and feral donkeys shapes desert wetlands (2022) Lundgren et al., Journal of Animal Ecology, https://doi.org/10.1111/1365-2656.13766

Image credit: CHUCAO, CC BY-SA 3.0, via Wikimedia Commons

The Crux

Trophic cascades (see Did You Know?) are an important part of many ecological systems. However, most of the world’s large predator species were lost around 10,000 years ago (potentially due to human impacts), thus limiting the role that predators could play in driving trophic cascades. Though large predators were lost, many large herbivores are still around, which means it is difficult for a smaller predator to take down/consume these herbivores, much less have an effect large enough to drive a trophic cascade.

In the United States, large felines such as cougars (Puma concolor) are known to predate large equid species (such as feral horses or donkeys), but much of the ecological literature assumes/claims that cougars do no exert a strong enough pressure to consider them “significant” predators of these equid species. Specifically, some reports state that these species don’t have any natural predators, and other reports echo the claim. Today’s authors report on a novel trophic cascade between the cougar, feral donkeys (Equus africanus asinus), and wetland vegetation.

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Surprises From the Past: The Revelations of Ancient DNA

Forest Tundra on the Taymyr Peninsula between Dudinka and Norilsk near Kayerkan, Russia, taken in 2016. Was it always look like this? Should it look like this?
Image Credit: Ninaras, CC BY 4.0, Image Cropped

Although obtaining ancient DNA can be quite a headache, it is a very rewarding headache. After all the work that goes into obtaining DNA from a bone, fur, hair, or Viking’s leftover meal, researchers have to make sense of the apparent random sequence of nucleotide bases. But once that’s taken care of, there are a series of really interesting questions we can start to answer. Were DNA strands that are present in the modern times inherited from the past? How similar are today’s species to their forebears? Where is my pet velociraptor?

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